Commercial crops are often the targets of attack by insects. Insect can have a significant negative effect on crop yield. Chemical insecticides have been effective in eradicating insect infestations; however, there are disadvantages to using chemical insecticides. Chemical insectidal agents are not selective and may exert a negative effect on beneficial insects and other organisms as well as the targeted insect. Chemical insectidal agents may persist in the environment and generally are slow to be metabolized, if at all. They accumulate in the food chain, and particularly in the higher predator species, where they can assert negative effects. Accumulations of chemical insectidal agents also results in the development of resistance to these chemical tools.
The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major pest of corn in the United States. The western corn rootworm overwinters in the egg stage in fields where corn was grown the previous season. The eggs hatch from late May through June. Thereafter, the larvae pass through 3 larval stages, or instars, feeding upon the corn root system. Following completion of larval development, the larvae transform into pupae, which are white and immobile. Adults of western corn rootworms begin to emerge in early July and continue to emerge from the pupae stage into August. Adult beetles feed on the corn foliage and silk. Female beetles lay the vast majority of their eggs in the soil of cornfields during August and early September. Western corn rootworm larvae can survive only on corn and a few other species of Poaceae (Branson and Ortman, J. Econ. Entomol. 60: 201-203 (1967); Branson and Ortman, J. Econ. Entomol. 60: 201-203 (1967)). Larval root feeding decreases plant vigor by reducing the water and nutrients supplied to the developing corn plants. Extensive root damage weakens the root system and makes the plants more susceptible to lodging (plants lean over or elbow), which eventually reduces corn yield and often results in death of the plant. Lodged plants are difficult to harvest resulting in further yield losses. The western corn rootworm adults feed upon corn leaves, which can slow plant growth and, on rare occasions, kill plants of some corn varieties. The western corn rootworm cause economic losses throughout the Midwest and in certain eastern and northeastern states where corn is produced.
Control of corn rootworms has been partially addressed by crop rotation. However, economic demands on the utilization of farmland restrict the use of crop rotation. In addition, the spread of at least one strain of rootworm has been documented in which female oviposition occurs in soybean fields, which further complicates crop rotation strategies. Therefore, chemical insecticides are relied upon most heavily to guarantee the desired level of control. Over $250 million worth of insecticides are applied annually to control corn rootworms alone in the United States. Even with insecticide use, rootworms still can cause over $750 million worth of crop damage each year. The use of chemical insecticides to control corn rootworm has several drawbacks. Continual use of insecticides has allowed resistant insects to evolve. Situations such as extremely high populations of larvae, heavy rains, and improper calibration of insecticide application equipment can result in poor control. Chemical insecticides used for corn rootworm control often raises environmental concerns such as contamination of soil and of both surface and underground water supplies, because many of them are toxic to humans, wildlife and other nontarget species. As a result, much research has been concentrated in the area of biopesticides.
Thus, there is a need for alternative methods for controlling or eradicating insect infestation on or in plants; methods which are selective, environmentally safe, non-persistent, biodegradable, and that fit well into pest resistance management schemes.
Disclosed herein is a non-Burkholderia cepacia complex, non-Burkholderia plantari, non-Burkholderia gladioli, Burkholderia sp., in particular, Burkholderia A396 sp. nov. rinojensis (NRRL Accession No. B-50319, a.k.a., 206) that can decrease Diabrotica infestation and/or increase crop yield. It is non-pathogenic to vertebrates, such as birds, mammals and fish, as is described in, for example, U.S. Pub. No. 2011-0207604 and U.S. application Ser. No. 13/843,971. Methods of growing the Burkholderia sp. and making a composition of Burkholderia sp. and its products (e.g., a whole-cell broth) are also described in U.S. Pub. No. 2011-0207604 and U.S. application Ser. No. 13/843,971.